The present exemplary embodiments relate to the imaging arts, and find particular application in conjunction with low and high-density cell detection, locating, and identifying in blood smears, biological assays, and the like across distinct imaging systems, and will be described with particular reference thereto. However, it is to be appreciated the exemplary embodiments will also find application in imaging, locating and identifying other types of low or high-density features on various substantially planar surfaces and samples, such as imaging semiconductor wafers, imaging particulate contaminants in fluids or thin solid films, and so forth, with such imaging finding specific uses in the printing arts, electronic arts, medical arts, and other scientific and engineering areas.
In rare cell studies, a particular problem arises due to the typically low concentration of the rare cells in the blood or other body fluid. In a typical rare cell study, blood is processed to remove cells that that are not needed. Then a fluorescent material is applied that attaches to antibodies, which in turn selectively attach to a cell surface or cellular protein of the rare cells. The cellular proteins may be membrane proteins or proteins within a cell, such as cytoplasm proteins. The antibodies may also attach to other types of molecules of the rare cell, as well as to DNA.
The fluorescent material may be a fluorescent marker dye or any other suitable material which will identify the cells of interest. A smear treated in this manner, which may include the blood and/or components of the blood, is prepared and optically analyzed to identify rare cells of the targeted type. For statistical accuracy it is important to obtain as large a number of cells as required for a particular process, in some studies at least ten rare cells should be identified, requiring a sampling of at least ten million cells, for a one in one-million rare cell concentration. Such a blood smear typically occupies an area of about 100 cm2. It is to be understood, however, that this is simply one example and other numbers of cells may be required for statistical accuracy for a particular test or study. Other cell identifiers which are being used and investigated are quantum dots and nano-particle probes. Also, while a rare cell is mentioned as a one-in-one-million cell concentration, this is not intended to be limiting and is only given as an example of the rarity of the cells being sought. The concepts discussed herein are to be understood to be useful in higher or lower levels of cell concentration.
In this regard, the ability to scan large numbers of cells at a high rate is considered a key aspect which increases the throughput of testing processes. Therefore, it is considered valuable to provide a system which improves the speed, reliability and processing costs which may be achieved by cell detection systems and/or processes.
Several-aspects may be considered as useful in increasing the throughput and reliability of scans at high rates of speed. For example, it would be useful to have a scanning system which permits high-speed scans in an accurate reliable manner, and a manner for increasing the accuracy with which cell detection occurs which includes decreasing a number of false or ghost images which may exist. While at the same time, maintaining or increasing the amount of data collected during a scan.